Locking pin and method for locking a gun barrel to a gun frame



Sept. 2, 1969 G. WI ELM 3,464,136

AND ME" LOCKING PIN l R LOC G A GUN BARREL TO A FRAM Filed April 1, 1968 [N VEN TOR.

I Gary mlizelm BY United States Patent US. C]. 42-75 3 Claims ABSTRACT OF THE DISCLOSURE A method and means for locking a gun barrel within its seat in a gun frame utilizing a sequence of drilled holes and a force fit locking pin having a tapered end bearing on a tapered wall inside the frame.

vThe object of this invention is to enable a lock pin to be used to lock a gun barrel to a gun frame without marring the finished and polished exterior frame surfaces.

Another object is to facilitate the economical and rigid assembly of a gun barrel to a gun frame.

Still another object is to provide a means for locking such members together to withstand the stresses created by firing the weapon.

Further objects will appear from the description which follows.

In the drawings in which the same numeral refers to the same or a similar part:

FIGURE 1 is a side view of a pistol embodying this invention.

FIGURE 2 is an enlarged section on line 2-2 of only the frame of FIGURE 1 prior to its surface finishing and polishing and prior to its assembly with the barrel.

FIGURE 3 is an enlarged section on line 22 of the frame of FIGURE 1 after insertion of the barrel and the drilling of the hole to receive the locking pin.

FIGURE 4 is an enlarged side view of the locking pin.

FIGURE 5 is an enlarged side view of the seating of the tapered end of the locking pin in the tapered end of the hole in the frame and barrel.

FIGURE 6 is a side view of the barrel seated and locked in the frame with a portion of the frame broken away at the breech end of the barrel.

Referring to FIGURES l and 6, gun barrel 1 has its breech end seated in a cavity 4 of gun frame 2, being locked therein by locking pin 3. Only the tip of locking pin 3 is visible in FIGURE 1, being seen in hole 5.

The method by which this is accomplished without marring the exterior surfaces of frame 2 requires that as part of the usual machining operations on a gun frame a blind hole 5 is drilled into one side of frame 2 and pilot hole 6 drilled a distance substantially the length of the head of locking pin 3 into the other side of frame 2, both holes being coaxial with a tangent to circular cavity 4 as shown in FIGURE 2.

Thereafter frame 2 may be finished and its exterior surfaces polished or otherwise given a final surface finish. Next barrel 1 is forced into cavity 4 to its desired final location therein. Following this joining of the barrel and frame, hole 7 of slightly less diameter than that of pilot hole 6 is started therein and is drilled through frame 2 and portion of barrel 1 to open out in blind hole 5 but stopping a short distance from the opposite face of frame 2. Hole 7 terminates in a taper 8.

Drilling of hole 7 thus does not mar either surface of frame 2.

Locking pin 3 is of diameter suited to force fit it into hole 7 with head 12 of diameter sufiicient to clear pilot hole 6, again a measure to protect the finished outer surface of frame 2. The length of locking pin 3 is less than the depth of hole 7 and it ends in a taper 9 of greater angular form than taper 8 of hole 7. A knurled section 11 is separated from head 12 by groove 10.

When locking pin 3 is driven into hole 7 it comes to rest with the shoulder of its taper 9 bearing on the shoulder of taper 8 as shown in FIGURE 5, its flat base being clear of contact with frame 2. When locking pin is driven into this final lodgement, metal scrapings that may result from the knurled portion cutting into the metal of the frame will collect in groove 10.

By causing the locking pin to come to rest with tapered surfaces abutting, the impact of the driven pin against the frame will not fall on a thin wall section of the frame with the danger of fracturing it.

The method shown may, with or without modification, be used in other assemblies that are locked by the insertion of a driven force fit pin.

What I claim is:

1. The combination of a gun barrel, gun frame, and lock pin comprising:

a gun frame having a longitudinal cavity therein,

a gun barrel with its breech end within and co-exteusive with said cavity,

a hole in the frame transverse to the longitudinal cavity and with its axis tangential thereto, opening out at one end in an exterior side surface of the frame and terminating at the other end in a taper a spaced distance from the other exterior side surface of the frame, and

a lock pin having a tapered end of greater angular form than the taper in the hole, in force fit engagement within the hole with its tapered surface in partial contact with the tapered surface of the hole.

2. The combination of a gun barrel, gun frame, and

lock pin comprising:

a gun frame having a longitudinal cavity therein,

a gun barrel with its breech end within and coextensive with said cavity,

a hole in the frame transverse to the longitudinal cavity and with its axis tangential thereto, opening out at one end in an exterior side surface of the frame and terminating at the other end in a taper a spaced distance from the other exterior side surface of the frame, and

a lock pin having a tapered end of greater angular form than the taper in the hole, in force fit engagement within the hole with the shoulder of its tapered surface in contact with the shoulder of the tapered surface of the hole.

3. The method of locking a gun barrel to a frame consisting in:

forming a frame with a longitudinal circular cavity to receive and hold a gun barrel in frictional engagement therein,

drilling a blind hole in one side of the frame and a blind hole of lesser diameter than the first in the other side of the frame, both coaxial with a tangent to the cavity,

press fitting the breech end of the gun barrel into the cavity in the frame,

drilling a hole of lesser diameter than the larger of the said two blind holes and coaxial therewith, starting Within the said larger hole and terminating in a tapered end a spaced distance from the opposite side of the frame,

driving a pin having a tapered end into such hole in close fit engagement with the barrel and frame until its tapered end comes to rest on the tapered surface of the hole.

4 References Cited UNITED STATES PATENTS 406,032 7/ 1889 Davenport 42-75 429,110 6/ 1890 Armington et a1. 4275 5 1,381,291 6/1921 Dygert 42-75 BENJAMIN A. BORCHELT, Primary Examiner C. T. JORDAN, Assistant Examiner 

